Well, not anytime soon for sure. Next patch tomorrow brings Frontline mode which apparently is also season-based, so very unlikely to have a new Ranked season while that is running. And afterwards there is the next (short) CW campaign until June 12th which would also conflict with Ranked grindmode. Maybe they'll run another season after the campaign so people can farm bonds for the reward tanks.

In general WG is very tight-lipped about disclosing timelines regarding in-game stuff. Even the leaks of third-party sites have mosty dried up for the last few months (other than official "leaks" to promote new premium tanks).